<!DOCTYPE html>

<html>
<head>
  <style>
    .container {
      width: 120px;
      position: relative;
      left: 50px;
      z-index: 0; /* create stacking context */
      border: 1px solid black;
      background-color: white;
    }
    
    .box {
      position: relative;
      width: 100px;
      height: 100px;
      margin: 10px;
      background-color: blue;
    }

    .force-layer {
      transform: translateZ(-1px);
    }

    .rotate-45deg {
      transform: rotate(45deg);
    }

    .yellow {
      background-color: yellow;
    }

    .gray {
      background-color: gray;
    }

    .green {
      background-color: green;
      outline: 1px solid black;
    }
    
    .animating1 {
      animation: translate1 2s linear infinite alternate;
    }
   
    @keyframes translate1 {
      from { transform: translate(0px, -110px); }
      to   { transform: translate(0px, 700px); }
    }
  </style>
  <script>
    if (window.testRunner) {
      testRunner.dumpAsText();
      testRunner.waitUntilDone();
    }

    function queueBoxForAnimation(elementId, animationClass, callback) {
      var box = document.getElementById(elementId);
      box.addEventListener('animationstart', callback, false);
      box.classList.add(animationClass);
    }
      
    function runTest()
    {
      queueBoxForAnimation("to-animate1", "animating1", animationStarted);
    }
    
    function animationStarted()
    {
      var layerTrees = "";

      if (window.testRunner) {
        var layersElement = document.getElementById('layers');
        // Make sure we don't include the #layers element in the tree. The text size
        // might differ between platforms.
        layersElement.style.display = "none";
        var layerText = internals.layerTreeAsText(document);
        // The animation can progress before the start event is handled, so remove the
        // effects as they can vary.
        layerText = layerText.replace(/\[.*,.*,.*,.*\]/g, '[...]');
        layerTrees = "Before:\n" + layerText;
      }

      // Rotate the first green box, so that it overlaps the first gray box in the container.
      // That should force the creation of composited layers for all the other green boxes.
      document.getElementById("first-green-box").classList.add("rotate-45deg");

      if (window.testRunner) {
        var layerText = internals.layerTreeAsText(document);
        // The animation can progress before the start event is handled, so remove the
        // effects as they can vary.
        layerText = layerText.replace(/\[.*,.*,.*,.*\]/g, '[...]');
        layerTrees += "\nAfter:\n" + layerText;
        layersElement.style.display = "block";
        layersElement.innerText = layerTrees;
        testRunner.notifyDone();
      }
    }
    window.addEventListener('load', runTest, false);
  </script>
</head>
<body>
  <!-- Testing that compositor doesn't create unnecessary composited layers when they could be drawn in parents backing texture. 
       The green boxes should not have composited layers.
  -->
  <!-- This div will not get a layer -->
  <div class="box gray"></div>
  <div id="to-animate1" class="box"></div>
  <div class="container">
    <!-- Force a composited box inside the container. The fact that there's an animation going behind the parent container, 
    should not force the remaining children of this element create their own composited layers. -->
    <div class="box gray force-layer"></div>
    <!-- This following have no reason to get a layer, as the parent will get one. -->
    <div id="first-green-box" class="box green"></div>
    <div class="box green rotate-45deg"></div>
    <div class="box green"></div>
  </div>
  <!-- This div will also get a layer -->
  <div class="box yellow"></div>
  <pre id="layers">Layer tree goes here in DRT</pre>
</body>
</html>
